The Past Is A Terrible Thing
by FreakingOutAlways
Summary: When a new case reawakens memories that Sherlock wanted forgotten, he knows this is a case he can't face with just his friends beside him. He calls upon the sister no-one knew about as support, but as time goes they realise, they are way out of their depth, and the childhood they tried so hard to keep secret, may be revealed. The Past Is A Terrible Thing. Post season 2.
1. Chapter 1

It was amazing how quickly things went back to normal after your best friend came back from the dead, John mused to himself.

It had only been a fortnight since Sherlock had returned and John had punched him in the face, but things were already going back to the way they were before Sherlock had taken a swan dive of the roof of Hospital. Sherlock was back as the Consulting Detective of Scotland Yard, 221B Baker Street was alive once more with the sound of gunshots and violins, and John was now chasing criminals down alleyways more than ever. And he loved every second of it. Well, apart from the nightmares. Those were still ever present, and he hated them.

Sherlock had changed slightly. A whole year away from everyone he cared about had made him a whole lot more sociable. When he thought John wasn't looking, John saw Sherlock shooting him looks, like he couldn't believe John was there. John was fine in the long run. It was just the nightmares and flashbacks that bothered him now. Two weeks ago, he had been a drunken wreck, with no job or money, sobbing on the sofa.

Sherlock's head jerked up from where it was bent over the paper.

'Lestrade is at the door,' Sherlock said calmly, looking back down at the paper. John rolled his eyes, hiding a secret smile. It was good to have him back.

'I'm glad to be back as well ,John' Sherlock said serenely, turning the page, seemingly in response once again to John's thoughts. How did he do that?

Sure enough, footsteps were heard on the stairs a moment later, and Lestrade burst through the door.

Lestrade had been having nearly a bad a time of it as John. He too had lost his job, his reputation and the young man that was more like a son to him than anything else. He and John had become extremely close over the last twelve months. When Sherlock had returned, and his innocence proved, (long story, involving a mobile phone, a dead but alive woman and an autopsy) Lestrade had immediately been given his job back, a raise and an apology, which was a lot more than John got from his work place but he wasn't exactly complaining about having the detective inspector back around. Sherlock's brain would explode without any cases to work on, and someone needed to keep Anderson and Donovan in line, who were not as convinced about Sherlock's innocence as the rest of the world. If John heard one more snide insult out of Anderson's mouth, all the kings horses and Sherlock's big brother could not retrain him from kneeing Anderson in the groin.

'We've got a case' Lestrade said, breathless, leaning against a nearby chair for support, as he staggered through the door.

'Obvious' Sherlock said dismissively, 'Give me details'

'Wounds are unusual, never seen any like them, the children in question are supposed to be on holiday in Florida at the moment and-'

'Wait, children?'

John stood from where he was sitting in his chair, eyes wide in disbelief. Sherlock too, had looked up from the paper and John could see a glint of remorse behind the ice-cold façade he had adopted, and maintained so well.

Lestrade suddenly seemed about ten times older. He sighed and ran a hand through his silver hair.

'Yes John,' he replied, wearily. 'Toby and Stephanie Sting . Six and four years old. Mother dead, Father imprisoned for fraud. They were in the care-system by the age of three. Their adopted parents took them to Disney but-'

'I'll take the case.' Sherlock said, interrupting Lestrade's babble. Lestrade's mouth dropped open.

'You will?' he asked, disbelievingly. 'Why?'

Sherlock turned his head away, stood up and put on his trademark black coat and blue wool scarf, which had miraculously not been lost on his year long journey through hell, ignoring Lestrade completely.

'Sherlock.'

'John!' he called, 'Get your shoes on, we're going out!'

'Sherlock!'

'John, please hurry up, the idiot in chief, Anderson has probably detonated most, if not likely all of the evidence already, if we don't go now we will never be able to study the ashes that remain! Which, knowing that dolt,-'

'SHERLOCK!' thundered Lestrade. 'For God's sake, will you please just shut up and listen? If you're going to take this case, you should know that this has happened before.'

'What?' Sherlock cried, sounding extremely put out, 'why didn't you tell, that is very important information!'

'It was another team! The case was closed, apparently they thought the COD it was some kind of wild animal mauling,' at this, Sherlock snorted, 'But then it happened again, their conclusion didn't match up, and the boss transferred the case to my team.'

'Is this is the same boss that ordered the arrest on Sherlock, sacked you, didn't believe in Moriarty and who I head-butted in the face' inquired John dangerously.

Lestrade looked rather uncomfortable. That was all the information John needed. He went a funny shade of red and opened his mouth, no doubt to let out a stream of swear words and insults describing the Detective Chief Inspector, but Sherlock cut in, rather sharply and completely out of character.

'Oh, that's enough John! That whole debacle was a year ago, and you've already broken the man's nose! This is about children being murdered, John!' Sherlock paused, taken in the rather ashamed expression on the man's face, and ended in a slightly softer tone of voice.

'Don't forget that, John'

Then, at once, he was back to his original, son of a banana self, shouting orders rapidly at the Lestrade, so fast that John completely missed them, and as he exited the living room, yelling as he went that John's shoes were under the sofa where he had shoved them last night..

Muttering, about irritating, genius roommates, John tugged his shoes out from under the sofa, stuck them on his feet, and then jogged down the stairs to catch up with Sherlock, who had already hailed a cab, (yet another of the Sherlock mysteries John had yet to figure out; why did they always stop for _him_?) grimacing in response to the sympathetic glance Lestrade shot him.

They may be glad to have Sherlock back, but he was still _really_ annoying!

'John?'

'Yes Sherlock?'

'You have your shoes on the wrong feet'

The crime scene was in a park, on a bridge overlooking the rose gardens. Blood was everywhere, a small lake around the drained cadavers, and dripping over the side. There is roughly two litres of blood in the human body. Imagine two litres of spilt milk on the floor. It was like that; only the liquid was scarlet, not white.

The bodies, horribly smaller than usual, were lying side by side. A small boy with dark, curly hair and an even younger girl, also with curly hair, but hers ginger. Their eyes stared sightlessly ahead, right through John, who had to swallow to steady his nerves. As John moved closer, he inhaled sharply, and turned his head away. The boy's arm was mangled terribly, nearly torn off, the white of bone and the shredded muscle extremely visible among all the horrible red, of torn, mutilated flesh.

The girl was just as bad. It looked as if someone had repeatedly fired nails into her arms and legs with a hammer, and missed several times before the nail sank into the flesh. The little skin John could see that wasn't crusted with blood was black with bruises, the limbs at several funny angles from the amount of times the limb had fractured.

He was dimly aware of Sherlock coming up behind him, and turned to say something that died in his mouth. Sherlock was staring at the children with a look of horror on his face, his pale, white skin morphing into a pale, sickly green. He had time to dive into the bushes before throwing up his breakfast into a clump of rhododendron.

'What's up with the freak?' The malicious voice was inevitable, but John still had to suppress a wave of white hot anger, as he turned to confront the enemy who was marching towards him. Sally Donovan was wearing her standard suit as uniform an ugly look on her face, and was watching Sherlock with a mixture of hate and twisted pleasure.

'Can't stomach it eh?' she called down to him, the spite rich and potent in her tone. 'I call it a guilty conscience! You killed them, didn't you?!'

'Sally!'

Just as John was about to snap, and toss the horrible woman over the side of the walkway, Lestrade's voice slammed some sense back into him. He couldn't kill her now, there were far too many witnesses, and besides, the bridge wasn't high enough. That and the fact that John Watson was not a murderer.

Lestrade looked furious; he had obviously heard the last comment and was literally trembling with fury.

'Sally Donovan,' he growled, 'I do not ever, want to hear that kind of comment out of your mouth again, alright? _Sherlock, _because, he does have a name, is doing us a favour and you should be grateful. If I hear anything like that again, I'll have your badge, got it?!'

'But sir, he's a bloody criminal! He probably just killed those children, and you expect me to kneel and worship the ground he walks on?!'

'I expect you' Lestrade hissed, 'to act civil and apologize. And no, he's not a criminal sergeant, all charges and accusations have been dropped. He is a free and clear man. Now apologize'

'Sir. . .'

'Apologize!'

'It's quite alright Lestrade' Sherlock said dismissively, still looking rather ill and shell-shocked, but no longer green around the edges.

'I've got all the data I need, I know who did it, it's now time for me and John to go home'

Sherlock began to walk, grabbing John's sleeve as he went and dragging him along.

'Hang on' Lestrade yelled, Sally momentarily forgotten. 'Who did it then? SHERLOCK!'

Sherlock, for once, was silent on the journey back, which was very unusual. As was Sherlock's behaviour, _at_ the crime scene. Normally, Sherlock would have been prancing about like his shoes were on fire, babbling on about tiny little details that painted the bigger picture. At the present time, in the Taxi ride home, Sherlock would usually texting, or typing something or other. But this time, he sat, stiff and upright, pale grey and tight lipped. Needless to say, John was worried.

When they finally returned to the flat, Sherlock went straight upstairs, ignoring 's mother henning,( 'Oh, Sherlock dear, you look ill, would you like me to bring up some hot soup? I always find that make me feel better, especially if I have a cold. . .') and went straight into his room, and shut the door, with a loud, firm and audible snap.

John took this as, 'I don't want to be disturbed, poke your head in and I'll bite it off!' and went off into the kitchen, to make the tea.

Behind the closed door, Sherlock was sitting on his bed, head in hands, shoulders shuddering with suppressed sobs. He was supposed to have escaped that life when he was six-teen! It was behind him, forgotten about, deleted! Why did he have to come back now?

Sherlock rubbed his eyes, which were now red-rimmed, and propped his head on his hands. He couldn't face this alone. Not again. He had done that once already, and that had nearly broken him. There was only one option available to him. He had to call the number.

Hands shaking, Sherlock slipped his phone out of his pocket and brought up the contact he needed. He brought it up to his ear, and heard the tell-tale buzz-buzzing that meant that somewhere, a phone was ringing.

'Hello?' A young girl was speaking. He recognized the voice, although it now had a Scottish accent.

'Hey, Tallulah.' He hated how his voice was shaking so badly, but Tallulah still seemed to recognize it, breathing in sharply, her voice filled with restrained joy.

'Sherlock? Is that really you?'

'Yeah, Tully, it's me. Listen, I need your help'

'What do you need?'

'I need you to come over here. He's back, and this time, he's killing children. I can't do this alone. Not again.'

The was a short, shocked pause.

'OK, I'm in,' said the voice determinately. 'When do you want me there?'

'As soon as you can' Sherlock replied, trying not to let his relief sound in his voice, and hung up. All that needed to be said, had been said.

In Scotland, Tallulah Holmes, hung up the phone and looked at her scandalized teacher, and applauding class-mates.

'I'm sorry Miss Franks, but I'm afraid this English lesson is going to be cut short,' she said distractly, gathering her thing in her rucksack, and preparing to leave the room.

'This is a Geography lesson!' the teacher cried, outraged as she watched the girl march towards the door.

'Is it' Tallulah asked. 'I hadn't realized. You really are a rubbish teacher, you should really quit. This job will bring your pupils only pain'

And she left.


	2. Chapter 2

Sherlock had no idea how long he sat there, in his room on the bed, staring into space. He couldn't even go into his mind palace, in fear of what memories from the past might linger there. Sherlock knew he was an egotistical moron. Sherlock liked to believe he could handle anything. Mutilated bodies at a crime-scene? He would go closer for another look. Three rifles aimed at the forheads of his closest friends? He would jump off a roof, although that one had nearly destroyed him. But the bodies of those children, (and just the fact that they were children is the worst part because despite what the dolts at Scotland yard think he does have a heart) was the one thing he couldn't manage on his own, even with everyone he cared about because _they didn't understand! S_o he had rung the number. And now she was probably going to punch him.

'Sherlock?'

Sherlock's head snapped up. John's disembodied head was poked inside the room. He looked grim, but as he looked at Sherlock more carefully, it grew to be more concerned.

Damn, red eyes.

Thankfully, John seemed to shrug off his confusion, and continued on the ominous train of thought.

'Sherlock' he said seriously, 'Lestrade and the lackeys are here. You're going to have to come out'

Sherlock nodded, but inside he was shaking. Where the devil was the girl? Soon as possible did not mean twelve hours later, he was going to have to specify this if, no _when_ she arrived.

He strode out into the living room, with all his usual bravado, and sighed in annoyance when he saw Anderson rummaging about in the fridge and Donnovan slouching in-

What the blazes.

'Donovan' he said icily, striding so he was in front of her. 'Vacate my seat'

She smirked at him, and said two words that she really, really shouldn't have.

'Make me'

Sherlock's eyes narrowed. It wasn't as if he'd ever _liked_ Donovan. He generally didn't like anyone with only a few exceptions most of which were in this building. But he _had_ respected her, despite the fact she was sleeping with _Anderson_ of all the rodents of the world. But that was gone now. And all he had left for her now was blatant dislike.

He swiftly walked behind the chair and with one hand, grabbed the rim of the head of the chair, and tipped Donovan right out onto the floor, and calmly flopped down onto the seat himself, smiling smugly all the while. Out of the corner of his eye he saw Lestrade smiling in pure pleasure and John frame shaking with silent laughter.

'So' Sherlock drawled,

'What was it that you wanted Lestrade?'

Lestrade stopped smiling and cleared his throat, ignoring his so-called team-mates dirty looks.

'Ah, yeah. Sherlock, you said you knew who did it. You know who killed those children. Who killed them?'

Sherlock didn't say anything for a moment. He felt like he was going to be sick again. His fingers were shaking and he knew they could see it.

'I can't tell you' His voice was hoarse. He hated it, hated how concerned Lestrade and John suddenly looked.

'I 'me sorry, but I really cann_ot_ tell you' He meant it too. He honestly couldn't.

'Sherlock. . .'

'NO'

Before he even knew what he was doing, Sherlock stood and hurled something at the mirror hanging on the wall above the fireplace. It took a few, horrifying seconds of hard breathing and staring wild eyes straight ahead of him, before Sherlock realized exactly what he had chucked at the undeserving wall. He bent down to grab the silver frame, trying not to cut himself on the glass shards around it. But John got there first.

Sherlock looked at him anxiously, as he stared at the photograph. It was the only one he had of Tallulah. She was about three years old in this picture, balanced on his knee, waving chubby fists at the camera lens. He must have set it to a timer, seeing how there was no-one left to hold it.

'Who is she?' John asked quietly .

Sherlock opened his mouth, but a new voice cut him off.

'My name is Tallulah Holmes. I 'me Sherlock's sister'

A girl was sitting cross-legged on the window ledge, obviously having climbed onto the fire escape. She was wearing a very tatty school uniform, of a _very_ short grey skirt, grubby white blouse, frayed tie and a pair of shiny, patent leather boots, zipped to her knees. Her hair was undone and straggly and sticking wetly to the sides of her face. Her clothes were dripping and her eye make-up was smudged and running in driblets down her cheeks. Cheeks that had those impossibly high cheekbones, belonging to a face that had eyes glimmering in mischief

She hopped off the windowsill and strutted over to Sherlock and embraced him in a huge hug, that, much to everyone's surprise, Sherlock returned, burying his face in her hair.

'His _sister?_' Anderson's voice was a mere squeak, and the girl's head popped back up, he face an expression of disgust.

'Shut your trap rodent' she snapped, 'Sibling bonding going on'

She paused, as if she had forgotten something.

'Oh, and he couldn't tell you because he needed me here' she informed Lestrade casually, who was staring at her with his mouth wide open. 'Moral support and all that. You remember don't you Greg?'

Abruptly, Greg walked forward and enveloped both her and Sherlock into a huge embrace, that drew a startled yelp out of its prisoners.

'Lestrade!' they moaned, in comical unison, 'Get off!'

Lestrade bounced back, beaming. 'Where have you been Tully?' he asked, as she ran a hand through the disaster that was her hair thanks to Lestrade's tousling and the abysmal weather.

'Long story' she returned. 'Now, you don't have the crime-scene photos do you? If it's who we think it is. . .' Her voice trailed off.

Lestrade clicked his fingers and, _very_ grudgingly, Donovan dropped a wad of paper into his hand from her jacket pocket, which was handed to the girl who snatched them and began to rifle through. 'Thank you Tweedle dum' she said, absent-mindedly, nodding to Donovan.

'Hey!' Piped up Anderson, 'Don't –'

'What did I say about shutting up Tweedle Dee!'

Tallulah stopped rifling through. She looked pale. Then she pushed past those standing around her and threw up into the sink.

'He's really back' she gasped, when she walked back in, wiping at her mouth and swaying slightly. 'He's really back'

'Who's back?!' screeched Donovan, who was clearly more than a bit frustrated and not at all pleased about her new nick-name.

Two sets of eyes met her. The queerest colour, mostly grey, but green or blue depending on the light, and both filled with earth-shattering terror that threatened to consume her.

'Our father' The girl whispered. 'Siger Holmes is back on the streets of Britain.'

Before anyone could grasp the truth of the situation, an angry voice from the corner was heard.

'What the bloody hell is going on!'

'oops'

'Yeah. We forgot about John'

'AGAIN!'

ent here...


End file.
